Method for structural health monitoring using a smart sensor system

Abstract

The structural health monitoring method of the present invention utilizes a sensor system to determine information about deformation, stress and/or damage in structural elements. The sensor system and the method employ at least one sensor which comprises a material having fully-reversible nonlinear elasticity. The method comprises associating at least one sensor including a material having fully-reversible nonlinear elasticity with a structural element in a manner whereby stress is transferred from said structural element to said sensor, propagating ultrasound through a portion of the sensor, receiving the ultrasound which has been propagated through at least a portion of the sensor and determining information about the structural element from attenuation and/or time of flight of said received ultrasound.

1. A method for monitoring a structure comprising:
 propagating ultrasound through at least a portion of a sensor associated with the structure in a manner whereby stress in the structure is transferred to said sensor; 
 receiving the ultrasound after it has propagated solely through said portion of the sensor, and 
 determining information relating to said structure from at least one of attenuation and time of flight of said received ultrasound, wherein said portion of said sensor comprises at least one material having fully-reversible nonlinear elasticity. 
 
     
     
       2. The method of  claim 1 , wherein said sensor is capable of operating within a temperature range of about 4 K to about 1000 K. 
     
     
       3. The method of  claim 1 , wherein said sensor is capable of operating within a temperature range of about 77 K to about 1000 K. 
     
     
       4. The method of  claim 1 , wherein said sensor is capable of operating within a temperature range of about 123.15 K to about 973.15 K. 
     
     
       5. The method of  claim 1 , wherein said sensor is corrosion resistant. 
     
     
       6. The method of  claim 1 , wherein said material having fully-reversible non-linear elasticity is selected from the group consisting of materials having MAX phases. 
     
     
       7. The method of  claim 6 , wherein the material having fully-reversible non-linear elasticity is selected from the group consisting of Ti 3 SiC 2 , Ti 2 AlC, graphite, hexagonal-boron nitride, mica, and hexagonal metals. 
     
     
       8. The method of  claim 7 , wherein the hexagonal metal is selected from the group consisting of Co, Mg, and Ti. 
     
     
       9. The method of  claim 1 , further comprising a step of identifying a site of deformation, stress or damage in the structure prior to associating the sensor with the structure. 
     
     
       10. The method of  claim 1 , wherein said method provides a maximum stress said structure experienced before a potential occurrence of structural failure. 
     
     
       11. The method of  claim 1  wherein said method provides a deformation history of said structure. 
     
     
       12. The method of  claim 1 , wherein said method provides an image of deformation, stress or damage to said structure. 
     
     
       13. The method of  claim 1 , wherein said information about said structure is determined from attenuation of said ultrasound by said sensor. 
     
     
       14. The method of  claim 1 , wherein said information about said structure is determined from time of flight of said ultrasound through said sensor. 
     
     
       15. The method of  claim 1 , wherein said sensor is bonded or clamped to said structure. 
     
     
       16. The method of  claim 1 , wherein said sensor material has a c/a ratio of at least 1.5. 
     
     
       17. A sensor system for monitoring a structure comprising:
 at least one sensor, wherein said sensor comprises at least one or more materials having fully-reversible nonlinear elasticity whereby association of said sensor with the structure allows stress to be transferred from said structure to said one or more materials; 
 at least one device for emitting ultrasound; 
 a receiver for receiving ultrasound; 
 wherein said device for emitting ultrasound and said receiver are arranged such that said ultrasound propagates only through said one or more materials when traveling between said device for emitting ultrasound. and said receiver; and 
 a data processing unit. 
 
     
     
       18. A sensor system of  claim 17 , wherein said sensor material has a c/a ratio of at least 1.5. 
     
     
       19. A sensor system as claimed in  claim 17 , wherein said sensor material is selected from one or materials having MAX phases and mixtures thereof. 
     
     
       20. A sensor system as claimed in  claim 18 , wherein said sensor material is selected from the group consisting of Ti 3 SiC 2 , Ti 2 AlC, graphite, hexagonal-boron nitride, mica, and hexagonal metals. 
     
     
       21. A sensor system as claimed in  claim 20 , wherein the hexagonal metal is selected from the group consisting of Co, Mg, and Ti. 
     
     
       22. A sensor system of  claim 17 , wherein said data processing unit determines information about a structure from at least one of attenuation and time of flight of said received ultrasound. 
     
     
       23. A sensor system of  claim 22 , wherein said system comprises calibration data and said data processing unit compares measured data to said calibration data to determine information about a structure. 
     
     
       24. A sensor system of  claim 23 , wherein said data processing unit determines one or more of a deformation history of said structure, an image of structural deformation of said structure or a maximum deformation experienced by said structure.